1. Field of the Disclosure
The present disclosure relates to a method and system for controlling the gait of a wearable robot based on a walking speed of a wearer and the intended gait of the wearer.
2. Description of the Related Art
The present disclosure relates to a gait control algorithm for reducing a load of a wearable walking robot. When a wearer who is wearing a robot walks, if the robot does not correctly reflect the intended gait of the wearer, the wearer will feel a load from the robot, and the load will be manifested as instability while the wearer is walking.
To overcome the above problem, the present disclosure provides a control algorithm which determines a speed at which the wearer intends to walk, and provides an imaginary reaction force corresponding to the intended movement of a foot that is being swung, thus reducing the load generated by the robot.
Existing wearable robots mainly use a force/torque sensor to determine the intended gait of a wearer. However, such a method requires measures to be implemented that solve problems induced by a chattering phenomenon and noise generation of the sensor when the wearer is walking. Further, the sensor is very expensive, and an additional amplifier circuit and signal processing board are required.
Therefore, according to an embodiment of the present disclosure, the use of the sensor can be minimized. For example, an On/Off switch which is comparatively inexpensive can be provided on the sole of each foot of the robot to determine the intended gait of the wearer.
A representative example of the conventional technique was proposed in Korean Patent Registration No. 10-1179159 B1, entitled “Foot sensor apparatus for wearable robot and method for determining intension of user using the same.” This conventional apparatus includes a first sensor provided on an upper surface of each foot of the wearable robot where the toes of the foot of the wearer are positioned, a second sensor provided on the upper surface of each foot of the robot where the ball of the foot of the wearer is positioned, a third sensor provided on the upper surface of each foot of the robot where the heel of the foot of the wearer is positioned, and a controller which determines the intended gait of the wearer based on signals from the first, second and third sensors.
When a load is applied to the first, second or third sensor, the corresponding sensor is turned on; and when no load is applied thereto, it is turned off. When the first, second and third sensors are each turned off, the controller determines that the foot of the wearer is in the air. When the first sensor is turned on but each of the second and third sensors is turned off, the controller determines that the foot is in a plantar-flexion state. When each of the first and second sensors is turned off and the third sensor is turned on, the controller determines that the foot is in a heel-strike state. When each of the first, second and third sensors is turned on, the controller determines that the entire foot of the wearer is brought into contact with the foot of the robot and that the wearer is standing up on the ground.
However, when using the above-mentioned conventional method, it is very difficult to precisely determine the intended gait of the wearer and to actively and variably control the robot. Furthermore, the number of sensors is relatively large, thereby increasing the production cost.
It is to be understood that the foregoing description is provided to merely aid the understanding of the present disclosure, and does not mean that the present disclosure falls under the purview of the related art .
(Patent document 1) KR10-1179159 B1